Well, if the NX is more powerful and it actually gets third party support (which I don't believe, but let's imagine it gets) I expect the Xbone to keep getting third party support, but I guess it will be "worse" perfomance wise. Maybe, maybe, developers will put less effort which can affect the relationship between them and Microsoft.
But hey, they can throw some money and get better deals, something that Nintendo won't do it, and we end like now. NX will be the one getting the Wii U "support".
Proud to be the first cool Nintendo fan ever
Number ONE Zelda fan in the Universe
Prediction: No Zelda HD for Wii U, quietly moved to the succesor
Predictions for Nintendo NX and Mobile